Structure 624804520100908 · St. John the Baptist County, LA

I0055 over I-55 Off Ramp @ US 51

Carries I0055 over I-55 Off Ramp @ US 51, 0.1 M N Of US 51.

Overall conditionGood

Set by its lowest-rated component: Deck and Substructure at 7 of 9.

How ratings work
Decksets the rating7/9 · Good
Superstructure8/9 · Very Good
Substructuresets the rating7/9 · Good
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT675 FT OVERALL100 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9 · sets the ratingSuperstructure 8/9Substructure 7/9 · sets the rating

675 ft end to end, longest span 60 ft: about 1.9 football fields. Lengths and the semi-truck on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built197551 years old
Length674.9 ft205.7 m
Daily traffic15,642counted 2021
Last inspectedJune 2023every 24 months

Location

StateLouisiana
CountySt. John the Baptist
Location0.1 M N Of US 51
CarriesI0055
CrossesI-55 Off Ramp @ US 51
Coordinates30.09481, -90.43900

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length674.9 ft (205.7 m)
Max Span60.0 ft (18.3 m)
Deck Width27.9 ft (8.5 m)
Deck Area1748.5 sq m
Main Spans10
Year Built1975

Traffic

Avg Daily Traffic15,642 (2021)
Truck Traffic26%
Lanes On Bridge1

Inspection & Ownership

Last InspectionJune 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number624804520100908

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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